Processes for coating surfaces of various machine components often employ cathodic arc deposition of a source material onto a surface. Cathodic arc deposition generally refers to physical vapor deposition techniques in which a cathode, composed of the coating source material, is vaporized. The vaporized source material then emits from the cathode and forms a film upon the surface of the machine component. Various materials can be vaporized and used as a coating via cathodic arc deposition, including, but not limited to, metallic, ceramic, and composite materials.
Cathodic arc deposition is often used when a film of a material having thermal resistive properties is desired on an outer layer of a machine component that may be exposed to excess or extreme heat. For example, a layer of such a film of a material having thermal resistive properties may be desired when designing and/or producing combustor panels for a combustor section of a gas turbine engine. Such combustor panels are exposed to intensely hot temperatures when the gas turbine engine is burning fuel in the combustor section. Cathodic arc deposition may provide a convenient method for coating such a panel during production.
However, panels that are coated via cathodic arc deposition often include holes such as, but not limited to, dilution holes. In prior cathodic arc deposition practices, the edges of said holes sometimes have improper coatings, in comparison to the coatings made on the outer surfaces of the panel. Oxidation distress may be present at said edges of the holes because, when using past processes for cathodic arc deposition, the coating on the edges of the holes may have inadequate thickness or extensive porosity. Oxidation along said edges may be harmful to the health and durability of the panel and, in turn, harmful to the health and durability of the machine with which the panel is associated.
Because health and durability of panels associated with machines is imperative in creating a durable product, a need exists for systems and methods for cathodic arc deposition which provide dense coatings of a source material along edges of the panel.